Tankless water heater isolation valve assembly

ABSTRACT

A tankless water heater (TWH) isolation valve includes a valve body having a plug valve port, a TWH port, a water distribution system port and a drain port. A plug valve includes at least one plug seal. The plug valve is controlled by a rotatable plug valve handle. The plug valve is disposed through the plug valve port and within the valve body. The rotatable plug valve handle includes a first plug valve handle position and a different rotated second plug valve handle position. In a normal operating mode in the first plug valve handle position, the TWH port is fluidly coupled to both of the drain port and the water system distribution port. In a drain mode, the TWH port is fluidly coupled to the drain port, and the water system distribution port is closed to the TWH port as blocked by the plug seal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. provisionalpatent application Ser. No. 63/024,571, TANKLESS WATER HEATER ISOLATIONVALVE ASSEMBLY, filed May 14, 2020, which application is incorporatedherein by reference in its entirety.

FIELD OF THE APPLICATION

The application relates to isolation valve assemblies, particularlyisolation valve assemblies for tankless water heaters.

BACKGROUND

Tankless water heaters heat a cold water flowed into the tankless waterheater inlet and provide an on demand heated water from the tanklesswater heater outlet. One common tankless water heater preventivemaintenance is to flow a mild acid such as a food grade vinegar throughthe internal pipes and heat exchanger to prevent buildup of depositsthat could degraded efficiency of the tankless water heater, or evencause a system failure. However, it is important to not introduce thecleaning solution into the water system, typically a potable watersystem including home hot water systems. Therefore, isolation valveassemblies are provided which allow for the tankless water heater inletand outlets to be isolated from the cold water feed and hot water supplylines during cleaning operations.

SUMMARY

A tankless water heater (TWH) isolation valve includes a valve bodyhaving a plug valve port, a TWH port, a water distribution system portand a drain port. A plug valve includes at least one plug seal. The plugvalve is controlled by a rotatable plug valve handle. The plug valve isdisposed through the plug valve port and within the valve body. Therotatable plug valve handle includes a first position and a secondposition. The second position is different and rotated from the firstposition. In a normal operating mode in the first position, the TWH portis fluidly coupled to both of the drain port and the water systemdistribution port. In a drain mode, the TWH port is fluidly coupled tothe drain port, and the water system distribution port is closed to theTWH port as blocked by the plug seal.

The TWH isolation valve can include a cold water isolation valve. TheTWH isolation valve can include a hot water isolation valve.

The TWH isolation valve can further including a pressure relief port.The TWH isolation valve can further including a pressure relief valvemechanically coupled to the pressure relief port and fluidly coupled tothe TWH port in both of the first position and the second position. Thepressure relief valve can be fluidly coupled to the TWH port in both ofthe first position and the second position.

A tankless water heater (TWH) isolation valve includes a valve bodyhaving a plug valve port, a TWH port, a water distribution system port,a first reversible port, and a second reversible port. The firstreversible port is disposed about opposite to the second reversibleport. A plug valve includes at least one plug seal, the plug valvecontrolled by a rotatable plug valve handle. The plug valve is disposedthrough the plug valve port and within the valve body. A drain valve ismechanically coupled to either of the first reversible port or thesecond reversible port, and a device mechanically coupled a differentone of the first reversible port or the second reversible port. Therotatable plug valve handle has a first position and a different rotatedsecond position. In a normal operating mode in the first position, theTWH port is fluidly coupled to both of the drain valve and the watersystem distribution port. In a drain mode, the TWH port is fluidlycoupled to the drain valve, and the water system distribution port isclosed to the TWH port as blocked by the plug seal.

The TWH isolation valve can include a cold water isolation valve. TheTWH isolation valve can include a hot water isolation valve.

The TWH isolation valve can further including a pressure relief port.The TWH isolation valve can further including a pressure relief valvemechanically coupled to the pressure relief port and fluidly coupled tothe TWH port in both of the first position and the different rotatedsecond position. The pressure relief valve can be fluidly coupled to theTWH port in both of the first position and the different rotated secondposition.

The TWH isolation valve can include a right hand TWH isolation valve orleft hand TWH isolation valve determined by which of the firstreversible port or the second reversible port is mechanically andfluidly coupled to the drain valve respectively. The different one ofthe first reversible port or the second reversible port can bemechanically and fluidly closed by a plug or a cap.

The plug or the cap can include a threaded plug or a threaded cap.

The different one of the first reversible port or the second reversibleport can be mechanically and fluidly coupled to a sensor disposedwithin.

The sensor can include a temperature sensor. The sensor can include apressure sensor.

The different one of the first reversible port or the second reversibleport can be mechanically and fluidly coupled to a diagnostic deviceduring R&D testing or manufacturing testing of the TWH.

A tankless water heater (TWH) isolation valve includes a valve bodyhaving a plug valve port, a TWH port, and a water distribution systemport. A plug valve includes at least one plug seal. The plug valve iscontrolled by a rotatable plug valve handle. The plug valve is disposedthrough the plug valve port and within the valve body. A drain portassembly includes at least one drain port, the at least one drain portan integral part of the valve body. The drain port assembly is disposedbetween the TWH port and the plug valve. The drain port assembly isoffset from the plug valve.

The TWH isolation valve can further including a second drain portdisposed opposite the at least one drain port, one of the at least onedrain port and the second drain port to accept a drain assemblyconfigured as either a right hand reversible TWH isolation valve or lefthand reversible TWH isolation valve.

The foregoing and other aspects, features, and advantages of theapplication will become more apparent from the following description andfrom the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the application can be better understood with referenceto the drawings described below, and the claims. The drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles described herein. In the drawings, likenumerals are used to indicate like parts throughout the various views.

FIG. 1 is a drawing showing an exploded view of a new plug typeisolation valve according to the Application;

FIG. 2A is a drawing showing top view of an isolation valve in a lefthand configuration, in the closed position;

FIG. 2B is a drawing showing back view of the isolation valve of FIG.2A;

FIG. 2C is a drawing showing another back view of the isolation valve ofFIG. 2A with section line AA;

FIG. 2D is a drawing showing an isometric view of the isolation valve ofFIG. 2A;

FIG. 2E is a cut away drawing of the isolation valve of FIG. 2A;

FIG. 2F is a cut away drawing of the isolation valve of FIG. 2A alongsection line AA;

FIG. 3A is a drawing showing top view of an isolation valve in a lefthand configuration, in the open position;

FIG. 3B is a drawing showing back view of the isolation valve of FIG.3A;

FIG. 3C is a drawing showing another back view of the isolation valve ofFIG. 3A with section line BB;

FIG. 3D is a drawing showing an isometric view of the isolation valve ofFIG. 3A;

FIG. 3E is a cut away drawing of the isolation valve of FIG. 3A;

FIG. 3F is a cut away drawing of the isolation valve of FIG. 3A alongsection line BB;

FIG. 4A is a drawing showing top view of an isolation valve in a righthand configuration, in the closed position;

FIG. 4B is a drawing showing front view of the isolation valve of FIG.4A;

FIG. 4C is a drawing showing another front view of the isolation valveof FIG. 4A with section line CC;

FIG. 4D is a drawing showing an isometric view of the isolation valve ofFIG. 4A;

FIG. 4E is a cut away drawing of the isolation valve of FIG. 4A;

FIG. 4F is a cut away drawing of the isolation valve of FIG. 4A alongsection line CC;

FIG. 5A is a drawing showing top view of an isolation valve in a righthand configuration, in the open position;

FIG. 5B is a drawing showing front view of the isolation valve of FIG.5A;

FIG. 5C is a drawing showing another front view of the isolation valveof FIG. 5A with section line DD;

FIG. 5D is a drawing showing an isometric view of the isolation valve ofFIG. 5A;

FIG. 5E is a cut away drawing of the isolation valve of FIG. 5A;

FIG. 5F is a cut away drawing of the isolation valve of FIG. 5A alongsection line DD;

FIG. 6A is a drawing illustrating how a right hand TWH isolation valvecan be transitioned to a left hand TWH isolation valve;

FIG. 6B is a drawing showing the transitioned right hand TWH isolationvalve of FIG. 6A as a left hand TWH isolation valve;

FIG. 7 is a drawing showing an exploded view of a tankless water heaterisolation valve assembly;

FIG. 8 is a drawing showing exemplary right and left plates;

FIG. 9 is a drawing showing an exploded view of a tankless water heaterisolation valve assembly with a hydraulic isolation feature;

FIG. 10 is a drawing showing exemplary right and left plates with anotch for the hydraulic isolation feature of FIG. 9 ;

FIG. 11A is a drawing showing the first two exemplary steps to sethydraulic isolation;

FIG. 11B is a drawing showing the last three exemplary steps to sethydraulic isolation;

FIG. 12 is a drawing showing an exemplary hot water heaters sharing acommon hot water main;

FIG. 13 is a drawing showing an exemplary pair of a hot water tanklesswater heater isolation valve assembly; and

FIG. 14 is a block diagram showing how any of the embodiments of the TWHisolation valves described hereinabove can be used with a TWH in abuilding TWH system; and

DETAILED DESCRIPTION

As described hereinabove, tankless water heaters heat a cold waterflowed into the tankless water heater inlet and provide an on demandheated water from the tankless water heater outlet. One common tanklesswater heater preventive maintenance is to flow a mild acid such as afood grade vinegar through the internal pipes and heat exchanger toprevent buildup of deposits that could degraded efficiency of thetankless water heater, or even cause a system failure. However, it isimportant to not introduce the cleaning solution into the water system,typically a potable water system including home hot water systems.Therefore, isolation valve assemblies are provided which allow for thetankless water heater inlet and outlets to be isolated from the coldwater feed and hot water supply lines during cleaning operations.

One problem with existing isolation valves for tankless water heaters isthat a right hand or left hand physical configuration is fixed at timeof manufacture. Such fixed structures mean either plumbing for a givenright hand or left hand structure or buying particular isolation valveswith a needed right hand or left hand physical configuration of portsand valves.

Therefore, there is a need for reconfigurable, swappable, or reversibleisolation valves for tankless water heaters.

Also, as part of the solutions, a relatively compact isolation valve fortankless water heaters was realized, in part, by introduction of a plugtype valve. With the symmetry achieved by the plug type valve, it wasrealized that opposing ports (e.g. threaded ports) can be introduced oneither side of a new type of compact isolation valve for tankless waterheaters. Either side port can be used for the purge valve/purge portpart, the different opposing port either capped by a threaded plug, oravailable as an option port, such as for an optional sensor, such as atemperature sensor.

FIG. 1 is a drawing showing an exploded view of a new plug typeisolation valve according to the Application. FIG. 1 shows an exemplaryisolation valve 100 typically used with tankless water heaters.Isolation valve 100 is shown configured with a pressure relief valve 141for the hot water side of a tankless water heater. A same new type coldwater isolation valve according to the Application (not shown in FIG. 1) can omit the pressure relief valve, and can also entirely omit thehigh pressure relief port. Continuing with FIG. 1 , a hot water sideisolation valve 100 includes four ports in one valve body. Port 193 isadapted to fluidly couple (typically by an intervening pipe) to the hotwater outlet of the tankless water heater. Water distribution systemport 198 is adapted to fluidly couple to a pipe of a hot waterdistribution system of a home or building. Port 196 is fluidly coupledto a drain assembly 121 which includes a second on/off valve 125controlled by handle 123. Port 195 fluidly couples to the pressurerelief valve 141 for the hot water isolation valve type.

In normal operation, isolation valve handle 103 is set so that hot waterflows normally out of a tankless water heater through the isolationvalve 100 and into the home or building hot water distribution system.In a drain operation, typically for testing or cleaning the tanklesswater heater, isolation valve handle 103 is turned 90° from the normaloperation position to the drain position. In a drain operation, port 198to the hot water distribution system of the home or building is closed.

Because of the new use of a plug valve, one aspect of what is new isthat there is always water fluidly coupled to port 196, the fluidconnection to the drain assembly 121, in both the normal operation andin the drain operation. One advantage of this new approach is that thedrain assembly, with its own on/off valve 125, can also be used fordiagnostic testing during normal water heater operation withoutinconveniencing hot water users in the home or building. Anotheradvantage is that plug valve assembly 102 is relatively simple comparedto more complex valves which open the normal hot water path, whileclosing the fluid path to the drain port. A plug valve can also be lesscomplicated and less costly to manufacture than a ball valve of theprior art, at least in part, because the relatively large machinedmetallic ball is no longer required.

Another feature of the new isolation valve is that is reversible forconvenient installation, where instead of some specific pipe pathsappropriate to a right hand configuration or a left hand configuration,either of a left side port 196, or a right side port 197 can accept thedrain assembly 121, while a plug 165 can be installed in the non-usedside. FIG. 1 shows a right hand configuration, where in a typicalinstallation below a tankless water heater, isolation valve handle 103will be on the right side, with the drain assembly pointed outward fromthe tankless water heater installation (typically outward from a wall onwhich the tankless water is mounted) (See FIG. 5D).

Another feature of the new reversible plug valve based isolation valve100, is that during a drain operation, the unused port (port 196 or port197) can be used to accept an option sensor, such as, for example anoption temperature sensor or pressure sensor. The extra port of theisolation valve 100 is particularly useful for factory testing, such asfactory R&D work, and post production testing operations. However, therecan also be diagnostic sensor uses during a drain operation for atankless water heater installed in the field. While the unused port(port 196 or port 197) is blocked during normal operation, the unusedport can still be used for a temperature sensor which does not extendall the way into the path of the rotating plug seal of the plug valve.The shallow mount temperature sensor can be used to measure thetemperature of the unitary metallic isolation valve body 190 (typicallybrass, however any suitable metallic material can be used) of theisolation valve 100 during normal operation, a temperature, accountingfor radiative loss to the ambient equipment room or basementtemperature, indicative of the hot water temperature and hot water flowrate. An isolation valve body 190 can also be manufactured of anysuitable non-metallic body as well, however then, the temperature sensorwould only be most useful when directly exposed to the fluid flow whenthe plug is blocking port 198 and the unused port (196 or 197) isfluidly coupled to the fluid flow.

An additional feature of the new reversible plug valve based isolationvalve 100, is that the ports 195, 196, 197 are located on a singleplane. In other words, the flow paths through the ports 195, 196, 197intersect. Placing the ports 195, 196, 197 on a single plane allows thevalve 100 to have a shorter height and more easily fit within a compactspace when installed on a tankless water heater. In the exemplaryembodiment shown, the drain ports 196, 197 are each located ninetydegrees from the pressure relief port 195. In other words the flow pathsthrough the ports 196, 197 are perpendicular to the flow path throughthe port 195.

Continuing with FIG. 1 , the new isolation valve 100 of the Applicationis described in detail beginning with a table of components forconvenient reference.

TABLE OR REFERENCE DESIGNATORS FOR FIG. 1 100 ISOLATION VALVE 101isolation valve plug 102 plug valve ASSEMBLY 103 isolation valve handle104 plug seal 105 isolation valve handle mounting screw 107 plug valvestem 109 reversible handle stop 111a right side normal operation stoppost 111b left side normal operation stop post 113 plug end seal 115spring clip 117 spring slot 121 drain ASSEMBLY 123 drain valve handle125 drain valve 127 drain cap 131 tankless water heater connectionASSEMBLY 133 compression nut 135 compression insert 137 compression portseal 141 pressure relief valve ASSEMBLY 163 unused port seal (sensorport) 165 unused port plug 190 isolation valve body 191 plug valve port193 tankless water heater port (hot water, FIG. 1) 195 pressure reliefport 196 right hand isolation reversible port 197 left hand isolationreversible port 198 water distribution system port (hot water, FIG. 1)

Plug valve—Plug valve assembly 102 makes possible the feature of theisolation valve 100 where the drain assembly is always available for useduring both normal and drain operations. As shown in FIG. 1 , in normaloperation, plug valve assembly 102 as controlled by isolation valvehandle 103 positions plug seal 104 over the unused port, thus opening anormal operation flow path between the tankless water heater (port 193)and the hot water distribution system port (port 198), thus providing anormal flow of hot water from tankless water heater to the home orbuilding.

In a drain operation, in the right hand configuration of FIG. 1 ,isolation valve handle 103 is rotated 90° towards the direction of thedrain assembly (typically away from the wall, pointing into the roomspace, handle about parallel to the long axis of the drain assembly).Now, the plug seal rotates to cover and close the hot water distributionsystem port 198.

The drain assembly 121 is always conveniently coupled to the tanklesswater heater, where the drain assembly 121 includes its own on/off drainvalve 125. Thus, particularly during factory R&D or post productiontesting, there can be diagnostic equipment fluidly coupled to a normallyoperating tankless water heater by opening drain valve 125 during normaloperation (or, during a drain operation).

The reversible nature of isolation valve 100 is set to a right handconfiguration or a left hand configuration by interchanging (reversingor swapping) the drain assembly 121 and the unused port plug betweenport 196 and port 197. The plug valve assembly 102 is always present inport 191. However, for the handle to turn outward towards the directionof the of the drain assembly 121, reversible handle stop 109 can beflipped over 180° and reinstalled under isolation valve handle 103 so asto stop either against the right side normal operation stop post 111 a,or the left side normal operation stop post 111 b.

Isolation valve plug 101 provides the plug valve frame for rotating plugseal 104 which rotates 90° with rotation of the isolation valve handle.Plug end seal 113 can be any suitable plug valve end seal, typically anO-ring seal as shown in FIG. 1 .

The plug valve assembly can be mounted in to the isolation valve body190 by any suitable mounting means, such as, for example, by threadednut, or by spring clip 115 and spring slots 117 as shown in FIG. 1 . Aretaining ring is another suitable method of assembling a plug valve(rotor) into the isolation valve body.

The drain assembly 121 includes an on/off drain valve 125 which iscontrolled by drain valve handle 123. Drain cap 127 can be a dust cover,such as, for example a plastic dust cap to keep the drain end clear offoreign debris and protect any machine threads. Or, drain cap 127 can bea threaded metal cap with an additional sealing washer or ring toprovide a second level of drain closure in addition to drain valve 125.Drain assembly 121 can be installed in either of port 196 or port 197,typically by any suitable connection, such as, for example, a threadedmechanical connection. For example, drain assembly 121 can include outermale threads and ports 196, 197, corresponding female machine threads.Any suitable mechanical coupling can be used. Typically, the drainassembly 121 is removable so that the drain assembly can be reversedbetween either of ports 196, 197, however, especially because suchisolation valves are typically only installed once, and are typicallynot reused, or re-configured during the normal lifetime of the isolationvalve, the drain assembly 121 can be supplied uninstalled with a onetime non-removable mechanical coupling means to either of ports 196,197, such as by a one-time mechanical mechanism (e.g. a onetime captivesnap lock), and/or adhesive or glue connection. More typically, ports196, 197 are threaded ports which may or may not include an additionalthreaded sealing compound (e.g. a threaded sealing compound suitable foruse with potable water). Most commonly, the drain assembly 121 andunused port plug 165 can be reversed in the field, both at the time ofinstallation, and later if a system is re-configured, or in the lesslikely event that the isolation valve is re-used for anotherinstallation.

Tankless water heater port 131 can be fluidly coupled to the tanklesswater heater by any suitable means. For example, compression nut 133,compression insert 135, and compression port seal 137 of FIG. 1 can beused to fluidly couple the isolation valve 100 to a tankless waterheater hot water outlet via a relatively short length of pipe. Anysuitable connection can be used, including, for example a flange mountto a tankless water heater.

An isolation valve 100 can be provided as an individual isolation valvepart. More typically isolation valves are sold in pairs, one for thetankless water heater hot water outlet (e.g. FIG. 1 ) and one for thecold water side without the high pressure relief valve, where the highpressure relief valve is typically only required on the hot water side.Or, such isolation valves 100 can be supplied with, or supplied alreadymounted to and fluidly coupled to the hot water outlet and cold waterinlet of a tankless water heater.

FIG. 2A through FIG. 5F show various views of an exemplary hot waterside isolation valve 100 in left hand and right hand configurations, inboth a normal operation open position and a drain operation closedposition. Here, open refers to the normal open path from the hot wateroutlet of the tankless water heater to the building hot waterdistribution system, and closed refers to the drain operation, where thenormal open path from the hot water outlet of the tankless water heaterto the building hot water distribution system is closed (shut off). Theconvention of left hand and right hand labels are used assuming theisolation valves are commonly installed underneath the tankless waterheater. However, there is no such mounting requirement, and thoseskilled in the art will recognize that there may be applications where aright side installation is defined by the isolation valve handle mountedon the right side as one faces the tankless water heater typicallymounted on a wall, or in other less common mounting applications, theisolation valve handle may be up, down, or left in a “right hand”isolation valve configuration. In other words is only important that thedrain valve is reversable between ports 196, 197, and that the isolationvalve handle 103 can be installed for any convenient 90° rotation bychoice of installation size and rotatable position of rotatable handlestop 109 within the isolation valve handle 103 and with respect to theright side normal operation stop post 111 a, or the left side normaloperation stop post 111 b.

Now, using the convention of the isolation valve mounted in the mostcommon manner underneath a tankless water heater mounted to a wall,

FIG. 2A is a drawing showing top view of an isolation valve 100 in aleft hand configuration, in the closed position. FIG. 2B is a drawingshowing back view of the isolation valve of FIG. 2A. FIG. 2C is adrawing showing another back view of the isolation valve of FIG. 2A withsection line AA. FIG. 2D is a drawing showing an isometric view of theisolation valve of FIG. 2A. FIG. 2E is a cut away drawing of theisolation valve of FIG. 2A. FIG. 2F is a cut away drawing of theisolation valve of FIG. 2A along section line AA.

FIG. 3A is a drawing showing top view of an isolation valve 100 in aleft hand configuration, in the open position. FIG. 3B is a drawingshowing back view of the isolation valve of FIG. 3A. FIG. 3C is adrawing showing another back view of the isolation valve of FIG. 3A withsection line BB. FIG. 3D is a drawing showing an isometric view of theisolation valve of FIG. 3A. FIG. 3E is a cut away drawing of theisolation valve of FIG. 3A. FIG. 3F is a cut away drawing of theisolation valve of FIG. 3A along section line BB.

FIG. 4A is a drawing showing top view of an isolation valve 100 in aright hand configuration, in the closed position. FIG. 4B is a drawingshowing front view of the isolation valve of FIG. 4A. FIG. 4C is adrawing showing another front view of the isolation valve of FIG. 4Awith section line CC. FIG. 4D is a drawing showing an isometric view ofthe isolation valve of FIG. 4A. FIG. 4E is a cut away drawing of theisolation valve of FIG. 4A. FIG. 4F is a cut away drawing of theisolation valve of FIG. 4A along section line CC.

FIG. 5A is a drawing showing top view of an isolation valve 100 in aright hand configuration, in the open position. FIG. 5B is a drawingshowing front view of the isolation valve of FIG. 5A. FIG. 5C is adrawing showing another front view of the isolation valve of FIG. 5Awith section line DD. FIG. 5D is a drawing showing an isometric view ofthe isolation valve of FIG. 5A. FIG. 5E is a cut away drawing of theisolation valve of FIG. 5A. FIG. 5F is a cut away drawing of theisolation valve of FIG. 5A along section line DD.

Isolation valves according to the Application can use threadedconnections. Any suitable threaded, compression, or soldered connectionscan be used.

Swappable Isolation Valve—FIG. 6A is a drawing illustrating how a righthand TWH isolation valve can be transitioned to a left hand TWHisolation valve;

FIG. 6A and FIG. 6B are drawings that illustrate how a right hand TWHisolation valve can be transitioned to a left hand TWH isolation valve.FIG. 6B is a drawing showing the transitioned right hand TWH isolationvalve of FIG. 6A as a left hand TWH isolation valve. A swappable, orreversible isolation valve is shown as a right hand TWH hot waterisolation valve 710, transitioned or re-configured as shown by arrow 799to a left hand TWH hot water isolation valve 720. Similarly, the lefthand TWH hot water isolation valve 720 can also be transitioned to aright hand TWH hot water isolation valve 710 by reversing the swappableprocess.

As shown in FIG. 6A and FIG. 6B, the swappable process (lower left)includes removing the drain assembly 121 from port 196, removing theunused port plug 165 from port 197, and removing the handle 103 byremoving the screw 105 to remove the reversible handle stop 109. Thereversible handle stop 109 is then flipped over or rotated and/or andthen reinstalled between handle 103 and the isolation valve body 190.Finally, the drain assembly 121 is installed into port 197, and the portplug 165 is installed into port 196.

Typically, a TWH isolation valve can be configured at time ofmanufacture, at time of manufacture of the TWH were installed into a TWHproduct, and/or in the field when an installer installs the isolationvalve, typically, but not necessarily, underneath a TWH.

A sensor or fluid connection to a diagnostic instrument (not shown inFIG. 1 , FIG. 7 ) can be optionally installed into port 196 in the lefthand configuration (right side of FIG. 1 , FIG. 7 ), or into port 197 inthe right hand configuration (left side of FIG. 1 , FIG. 7 ).

In summary, and generally, with reference to FIG. 1 , A tankless waterheater (TWH) isolation valve 100 includes a valve body 190 having a plugvalve port 191, a TWH port 193, a water distribution system port 198 anda drain port (196, FIG. 1 or 197 ). A plug valve 101 includes at leastone plug seal 104. The plug valve 101 is controlled by a rotatable plugvalve handle 103. The plug valve 101 is disposed through the plug valveport 191 and within the valve body 190. The rotatable plug valve handle103 includes a first plug valve handle position and a different rotatedsecond plug valve handle position. In a normal operating mode in thefirst plug valve handle position (FIG. 5A to FIG. 5D), the TWH port 193is fluidly coupled to both of the drain port (196, FIG. 1 or 197 ) andthe water system distribution port 198. In a drain mode (FIG. 4A to FIG.4D), the TWH port is fluidly coupled to the drain port (196, FIG. 1 or197 ), and the water system distribution port 198 is closed to the TWHport 193 as blocked by the plug seal 104.

Also, generally, with reference to FIG. 1 , a tankless water heater(TWH) isolation valve 100 includes a valve body 190 having a plug valveport 191, a TWH port 193, a water distribution system port 198, a firstreversible port 196, and a second reversible port 197. The firstreversible port 196 is disposed about opposite to the second reversibleport 197. A plug valve 101 includes at least one plug seal 104. The plugvalve 101 is controlled by a rotatable plug valve handle 103. The plugvalve 101 is disposed through the plug valve port 191 and within thevalve body 190. A drain valve 121 is mechanically coupled to either ofthe first reversible port 196 (FIG. 6A, left side, right hand isolationvalve configuration) or the second reversible port 197 (FIG. 6B, rightside, left hand isolation valve configuration), and a device (e.g.unused port plug 165) is mechanically coupled a different one of thefirst reversible port 196 or the second reversible port 197. Therotatable plug valve handle 103 has a first plug valve handle positionand a different rotated second plug valve handle position. In a normaloperating mode in the first plug valve handle position, the TWH port 193is fluidly coupled to both of the drain valve 121 and the water systemdistribution port 198. In a drain mode, the TWH port 193 is fluidlycoupled to the drain valve 121, and the water system distribution port198 is closed to the TWH port as blocked by the plug seal 104.

Yet another tankless water heater isolation valve assembly according tothe Application is shown in FIG. 7 and FIG. 13 .

FIG. 7 is a drawing showing an exploded view of a tankless water heaterisolation valve assembly 1000. In this exemplary embodiment, the drainports (isolation reversible port 196, and isolation reversible port 197)are now offset from the shut-off plug valve (e.g. raised above in FIG. 7). and the pressure relief port 195. In other words, the ports 196, 197are located on a separate plane from the port 195. The drain ports aretherefore unaffected by plug valve and are always in fluid contact withtankless water heater. One benefit of the arrangement of FIG. 7 , isthat the extra drain port can receive a sensor which is always incontact with the water. Any suitable sensor, including those describedhereinabove can be used. Typically, the sensor will be a temperaturesensor or a pressure sensor.

In FIG. 7 , both of the isolation reversible port 196 and isolationreversible port 197 are now raised above the isolation valve plug 101and the plug valve assembly 102. The isolation reversible port 196, andisolation reversible port 197 are now part of an isolation reversibleport assembly 1010. Shown for reference in FIG. 7 are center lines 1051,1061, and 1071. The Isolation reversible port assembly 1010 can be seento be aligned with center line 1061, offset (e.g. above in FIG. 7 ) andperpendicular to centerline 1051 of the plug valve assembly 102.

FIG. 8 is a drawing showing exemplary right and left plates. In FIG. 7 ,tab 1011 stops the rotation of stop plate 1009, and in turn handle 103.Stop plate 1009 includes a handle direction orientation mark 1705, sidedesignation text 1701, and plate stop ledge 1703. FIG. 8 is a drawingshowing exemplary right and left plates Exemplary retainer ring 1119(spring clip) snaps into trough 1117 to hold the plug valve assembly 102together. Exemplary fastener 1005 affixes handle 103 to the isolationvalve plug 101.

Isolation reversible port assembly 1010 is still physically part of thetankless water heater isolation valve assembly 1000, however the fluidflow through the isolation reversible port 196 and the isolationreversible port 197 is no longer controlled by the rotational positionof the plug valve assembly 102.

FIG. 13 is a drawing showing an exemplary pair of a hot water tanklesswater heater isolation valve assembly 1000 and a cold water tanklesswater heater isolation valve assembly 1101. Note that the cold watertankless water heater isolation valve assembly 1101 does not need thepressure relief port 195. The exemplary cold water tankless water heaterisolation valve assembly 1101 can optionally excludes isolationreversible port 197, or the isolation reversible port 197 can be presentto allow for reversibility.

In summary, and with respect to exemplary FIG. 7 , a tankless waterheater (TWH) isolation valve 100 includes a valve body having a plugvalve port 191, a TWH port 193, a water distribution system port 198. Aplug valve 101 includes at least one plug seal 104. The plug valve 101is controlled by a rotatable plug valve handle 103. The plug valve 101is disposed through the plug valve port 191 and within the isolationvalve body 190. A drain port assembly 1010 includes at least one drainport 196, the at least one drain port 196 an integral part of theisolation valve body 190. The drain port assembly 1010 is disposedbetween the TWH port 193 and the plug valve 101. The drain port assembly1010 (center line longitudinal axis 1061) is offset from the plug valve101 (center line longitudinal axis 1051).

FIG. 14 is a block diagram showing how any of the embodiments of the TWHisolation valves described hereinabove can be used with a TWH in abuilding TWH system.

The method of changing from a right handed to a left handedconfiguration can includes the following steps:

1) With purge valve facing the operator and handle placed in offposition (handle stem pointing towards the operator), pull handle offfrom the valve, disconnecting from the rotor (rotating plug)

2) Swap purge valve position with the brass plug on the opposite side ofthe valve

3) Rotate the whole valve assembly so the purge valve is again facingthe operator

4) Remove Handle stop marked as “RIGHT HAND” and replace withadditionally provided handle stop marked as “LEFT HAND”

5) Reattach handle to the rotor (rotor still in off position), with thehandle stem pointing towards the operator and in the same direction asthe purge valve

6) When complete, handle should now be on the left side, with operatorfacing purge valve, and handle stem pointing at the operator. Sealingportion of the rotor should be over the residential connection port forthe hot side valve.

7) Handle will now only rotate from pointing towards the operator to 90degrees downward pointing towards direction of the flow (away from TWHon the hot side).

Hydraulic Isolation feature—When used in modular installations, such aswhere a plurality of hot water heaters share a common hot water main, avalve assembly according to the Application which further includes ahydraulic isolation feature can be field configured to provide hydraulicisolation of units that need service or repair while other units remainoperating. FIG. 12 is a drawing showing an exemplary hot water heaterssharing a common hot water main.

FIG. 9 is a drawing showing an exploded view of a yet another tanklesswater heater isolation valve assembly with a hydraulic isolationfeature. FIG. 10 is a drawing showing exemplary right and left plateswith a notch for the hydraulic isolation feature of FIG. 9 .

The tankless water heater isolation valve assembly of FIG. 9 and FIG. 10is similar to the tankless water heater isolation valve assembly of FIG.7 and FIG. 8 with the addition of hydraulic isolation position notchesin the right and left stop plates.

To provide hydraulic isolation from a pressurized hot water main usingthe valve assembly of FIG. 9 and FIG. 10 , the pressure-activated sealcan be rotated 180 degrees from the bottom port to the upper port.

Generally, the plug valve is rotated into a hydraulic isolationposition, and mechanically set to that position by the hydraulicisolation position notch 901 of the stop plate 1009 (FIG. 9 , FIG. 10 )seating over the tab 1011 (FIG. 7 , FIG. 9 ).

As illustrated by the exemplary steps of FIG. 11A and FIG. 11B. FIG. 11Ais a drawing showing the first two exemplary steps to set hydraulicisolation. FIG. 11B is a drawing showing the last three exemplary stepsto set hydraulic isolation. First, A) With the valve in the closedposition (handle facing forwards), remove handle plug, handle and stopplate. B) Place handle back on rotor hub and rotate 180 degrees sohandle is facing rearward. C) Remove handle and re-install stop platealigning the notch (marked with a X) with the nub on the body. D)Re-install handle (facing to the rear) and handle plug. The valve willnow provide hydraulic isolation from a pressurized hot water main and belocked closed to prevent operation of water heater. Finally, E) To placeheater back in commission, reverse the above process.

It will be appreciated that variants of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be combined intomany other different systems or applications. Various presentlyunforeseen or unanticipated alternatives, modifications, variations, orimprovements therein may be subsequently made by those skilled in theart which are also intended to be encompassed by the following claims.

What is claimed is:
 1. A tankless water heater (TWH) isolation valvecomprising: a valve body having a plug valve port, a TWH port, a waterdistribution system port and a drain port; a plug valve comprising atleast one plug seal, said plug valve controlled by a rotatable plugvalve handle, said plug valve disposed through said plug valve port andwithin said valve body, said rotatable plug valve handle comprising afirst position and a second position, said second position different androtated from said first position; wherein in a normal operating mode insaid first position, said TWH port is fluidly coupled to both of saiddrain port and said water system distribution port; and wherein in adrain mode, said TWH port is fluidly coupled to said drain port, andsaid water system distribution port is closed to said TWH port asblocked by said plug seal.
 2. The TWH isolation valve of claim 1,wherein said TWH isolation valve comprises a cold water isolation valve.3. The TWH isolation valve of claim 1, wherein said TWH isolation valvecomprises a hot water isolation valve.
 4. The TWH isolation valve ofclaim 3, further comprising a pressure relief port.
 5. The TWH isolationvalve of claim 4, further comprising a pressure relief valvemechanically coupled to said pressure relief port and fluidly coupled tosaid TWH port in both of said first position and said second position.6. The TWH isolation valve of claim 5, wherein said pressure reliefvalve fluidly coupled to said TWH port in both of said first positionand said second position.
 7. A tankless water heater (TWH) isolationvalve comprising: a valve body having a plug valve port, a TWH port, awater distribution system port, a first reversible port, and a secondreversible port, said first reversible port disposed about opposite tosaid second reversible port; a plug valve comprising at least one plugseal, said plug valve controlled by a rotatable plug valve handle, saidplug valve disposed through said plug valve port and within said valvebody; a drain valve mechanically coupled to either of said firstreversible port or said second reversible port, and a devicemechanically coupled a different one of said first reversible port orsaid second reversible port; wherein said rotatable plug valve handlehas a first position and a different rotated second position; wherein ina normal operating mode in said first position, said TWH port is fluidlycoupled to both of said drain valve and said water system distributionport; and wherein in a drain mode, said TWH port is fluidly coupled tosaid drain valve, and said water system distribution port is closed tosaid TWH port as blocked by said plug seal.
 8. The TWH isolation valveof claim 7, wherein said TWH isolation valve comprises a cold waterisolation valve.
 9. The TWH isolation valve of claim 7, wherein said TWHisolation valve comprises a hot water isolation valve.
 10. The TWHisolation valve of claim 9, further comprising a pressure relief port.11. The TWH isolation valve of claim 10, further comprising a pressurerelief valve mechanically coupled to said pressure relief port andfluidly coupled to said TWH port in both of said first position and saiddifferent rotated second position.
 12. The TWH isolation valve of claim11, wherein said pressure relief valve fluidly coupled to said TWH portin both of said first position and said different rotated secondposition.
 13. The TWH isolation valve of claim 7, wherein said TWHisolation valve comprises a right hand TWH isolation valve or left handTWH isolation valve determined by which of said first reversible port orsaid second reversible port is mechanically and fluidly coupled to saiddrain valve respectively.
 14. The TWH isolation valve of claim 7,wherein said different one of said first reversible port or said secondreversible port is mechanically and fluidly closed by a plug or a cap.15. The TWH isolation valve of claim 14, wherein said plug or said capcomprises a threaded plug or a threaded cap.
 16. The TWH isolation valveof claim 7, wherein said different one of said first reversible port orsaid second reversible port is mechanically and fluidly coupled to asensor disposed within.
 17. The TWH isolation valve of claim 16, whereinsaid sensor comprises a temperature sensor.
 18. The TWH isolation valveof claim 16, wherein said sensor comprises a pressure sensor.
 19. TheTWH isolation valve of claim 7, wherein said different one of said firstreversible port or said second reversible port is mechanically andfluidly coupled to a diagnostic device during R&D testing ormanufacturing testing of said TWH.
 20. A tankless water heater (TWH)isolation valve comprising: a valve body having a plug valve port, a TWHport, and a water distribution system port; a plug valve comprising atleast one plug seal, said plug valve controlled by a rotatable plugvalve handle, said plug valve disposed through said plug valve port andwithin said valve body; and a drain port assembly comprising at leastone drain port, said at least one drain port an integral part of saidvalve body, said drain port assembly disposed between said TWH port andsaid plug valve, said drain port assembly offset from said plug valve.21. The TWH isolation valve of claim 20, further comprising a seconddrain port disposed opposite said at least one drain port, one of saidat least one drain port and said second drain port to accept a drainassembly configured as either a right hand reversible TWH isolationvalve or left hand reversible TWH isolation valve.
 22. The TWH isolationvalve of claim 20, further comprising a stop plate having a hydraulicisolation notch.
 23. A method for hydraulic isolation of a tanklesswater heater comprising: with a tankless water valve in a closedposition and with a tankless water valve handle facing forwards,removing a handle plug, said tankless water valve handle and a stopplate disposed under said handle; placing said tankless water valvehandle back on a rotor hub and rotating 180 degrees so that said handleis facing rearward; removing said tankless water valve handle andre-installing said stop plate by aligning a hydraulic isolation notch ofsaid stop plate with a nub on a body of said tankless water valve; andre-installing said tankless water valve handle facing rear and saidhandle plug wherein said tankless water valve provides a hydraulicisolation from a pressurized hot water main and said tankless watervalve locked closed to prevent operation of the water heater.